The present invention relates to a voltage converter scheme, and more particularly to a constant on-time pulse width control-based apparatus used in a voltage converter.
Generally speaking, a conventional constant on-time controller is usually limited by small ESR (equivalent series resistor) of its output capacitor. The conventional controller cannot effectively reflect/detect output voltage ripple due to that the ESR is too small. Some conventional schemes are proposed to improve the detection of output voltage ripple. However, a part of these conventional schemes cannot improve poor noise immunity and worse DC voltage regulation, and its signal gain for compensation is too low. In addition, another part of the conventional schemes may further limit the transient response. Additionally, another part of the conventional schemes may adopt a voltage mode control loop and necessarily needs a complicated compensation circuit design due to that it lacks of the current signal for its voltage mode control loop.